What is it?
The Mantoux tuberculin skin test (TST) is the standard method of determining whether a person is infected with Mycobacterium tuberculosis.
How is the TST Administered?
The TST is performed by injecting 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm. The injection is made with a tuberculin syringe.
How is the TST Read?
The skin test reaction should be read between 48 and 72 hours after administration. A patient who does not return within 72 hours will need to be rescheduled for another skin test.
Who Can Receive a TST?
Most persons can receive a TST. TST is contraindicated only for persons who have had a severe reaction (e.g., necrosis, blistering, anaphylactic shock, or ulcerations) to a previous TST. It is not contraindicated for any other persons, including infants, children, pregnant women, persons who are HIV-infected, or persons who have been vaccinated with BCG
How Often Can TSTs Be Repeated?
In general, there is no risk associated with repeated tuberculin skin test placements. If a person does not return within 48-72 hours for a test reading, a second test can be placed as soon as possible. There is no contraindication to repeating the TST, unless a previous TST was associated with a severe reaction.
Can TSTs Be Given To Persons Receiving Vaccinations?
Vaccination with live viruses may interfere with TST reactions. Please consult the local public health agency for instruction and information.
What are the different skin testing methods?
The public health agency will determine what test you need. The two tests include:
Two-Step Tuberculin Skin Testing (TST) Method:
- TST Administered
- TST read in 48-72 hours
- 2nd TST Administered within 1-3 weeks of the 1st TST reading
- 2nd TST read in 48-72 hours
One-Step Tuberculin Skin Testing (TST) Method:
- TST Administered
- TST read in 48-72 hour